package 集合.day3.demo1;

import java.util.HashMap;

public class Test2 {
    public static void main(String[] args) {
        HashMap hs=new HashMap();
        //hashmap的键和值都可以为Null
        hs.put("name",null);
        hs.put(new String("name"),"abc");
        System.out.println(hs.get("name"));

    }
}
